College Algebra (6th Edition)

see Properties of Roots of Polynomial Equations (page 382) 1. If a polynomial equation is of degree $n$, then counting multiple roots separately, the equation has $n$ roots. 2. If $a+bi$ is a root of a polynomial equation with real coefficients $(b\neq 0)$, then the imaginary number $a-bi$ is also a root. Imaginary roots, if they exist, occur in conjugate pairs. ------------------------ The graph (attached image) crosses the x-axis at three places,... f has 3 real zeros. It has a total of n=5 zeros, so two are conjugate complex numbers